Scaffold Exercises

Create exercise directory structures that pass pnpm ai-hero-cli internal lint, then commit with git commit.

Directory naming

• Sections: XX-section-name/ inside exercises/ (e.g., 01-retrieval-skill-building)
• Exercises: XX.YY-exercise-name/ inside a section (e.g., 01.03-retrieval-with-bm25)
• Section number = XX, exercise number = XX.YY
• Names are dash-case (lowercase, hyphens)

Exercise variants

Each exercise needs at least one of these subfolders:

• problem/ - student workspace with TODOs
• solution/ - reference implementation
• explainer/ - conceptual material, no TODOs

When stubbing, default to explainer/ unless the plan specifies otherwise.

Required files

Each subfolder (problem/, solution/, explainer/) needs a readme.md that:

• Is not empty (must have real content, even a single title line works)
• Has no broken links

When stubbing, create a minimal readme with a title and a description:

# Exercise Title

Description here

If the subfolder has code, it also needs a main.ts (>1 line). But for stubs, a readme-only exercise is fine.

Workflow

1. Parse the plan - extract s…